Answer:
a,c and d
Explanation:
- brain becomes smaller and lighter with age and although in absence of disease, it retains its structure and function.
- the brain shrinks, it pulls away from from the skull and the amount of amount of space between brain and skull doubles between 20 to 70 years of age.
- Blood flow reduces within the brain , which also uses less oxygen and glucose.
Hence, options a, c and d are correct.
